1. Field of the Invention
The present invention relates to a blood pressure measuring device (hereinafter also referred to simply as blood pressure monitor) having a cuff and a main-unit casing connected by a flexible connection tube.
2. Description of the Background Art
Recently, for early detection of lifestyle-related diseases whose main cause is hypertension or for blood pressure management, blood pressure monitors that can be used at home have become widespread. Usually, to measure a blood pressure value, a cuff including a fluid bag for pressing an artery located within a living body is wrapped around the body surface of the living body, and arterial pressure pulse waves caused in the artery by inflation and deflation of the wrapped fluid bag are detected to measure the blood pressure value.
Here, the cuff refers to a band-shaped structure that has a bladder and that can be wrapped around a part of a living body, for use in measurement of arterial pressure of an upper limb/lower limb by supplying such a fluid as gas or liquid into the bladder. Thus, the cuff is a term representing the concept including the fluid bag as well as a mechanism for wrapping the fluid bag around a part of the living body, and the cuff is also called arm band or manchette depending on the case.
For the so-called upper-arm blood pressure monitor using an upper arm as a site for taking a measurement, the structure is employed that connects, by an air tube which is a flexible connection tube, a main-unit casing in which for example a pump and a valve are provided that are components of an inflation/deflation mechanism for inflating/deflating an air bag serving as the fluid bag, and a cuff containing the air bag. Therefore, preferably the upper-arm blood pressure monitor is superior in terms of housing of these cuff, air tube and main-unit casing while the monitor is not in use, and it is required that the components can be housed compactly and that the act of housing the components is easy.
As examples of the upper-arm blood pressure monitor improved in terms of housing, those disclosed in Japanese Patent Laying-Open No. 03-097443 (hereinafter referred to as Document 1), Japanese Utility Model Laying-Open No. 64-019403 (hereinafter Document 2) and Japanese Utility Model Laying-Open No. 62-130606 (hereinafter Document 3) are known.
Document 1 discloses a blood pressure monitor using the Korotkoff method that is structured in the manner that a microphone serving as a detection unit provided in a cuff and a signal processing unit provided within a main-unit casing are connected by a signal line, an air tube serving as a connection tube connecting an air bag and an inflation/deflation mechanism and the signal line are formed as a composite tube where the air tube and the signal line are provided in parallel, and the composite tube is thermally processed into a spiral shape so that the composite tube is elastic and resilient. While the blood pressure monitor is not used, the cuff is housed in a cuff housing provided in the main-unit casing, and the composite tube including the air tube is housed in a composite tube housing provided in parallel with the cuff housing.
Further, Document 2 discloses a blood pressure monitor having a housing box prepared to separately contain a main-unit-casing housing which houses a main-unit casing and a cuff housing which houses a cuff, and these housings are connected to each other via a hinge. While the blood pressure monitor is not used, the main-unit casing is housed in the main-unit-casing housing and the cuff and an air tube are housed in the cuff housing.
Furthermore, Document 3 discloses a blood pressure monitor having a cuff housing case for housing a cuff that is provided in parallel with a main-unit casing, and the main-unit casing and the cuff housing case are structured in the manner that an opening for placing/removing the cuff in/from the cuff housing case takes two states, namely the state where the opening is covered with the main-unit casing and the state where the opening is not covered with the main-unit casing. While the blood pressure monitor is not used, the cuff and an air tube are housed in the cuff housing case and the cuff-housing case is attached to the main-unit casing in the manner that the opening for placing/removing the cuff in/from the cuff housing case is covered with the main-unit casing.
Other than the blood pressure monitors disclosed in Documents 1 to 3, blood pressure monitors improved in terms of housing in various ways are also known. However, many of them merely have, in a main-unit casing, a cuff housing for housing a cuff. Regarding the air tube, it is merely intended that the air tube is folded to be housed in an air-tube housing that is provided in parallel with the cuff housing or the folded air tube is inserted into and held in a hollow portion of a tubular cuff.
As described above, although the conventional blood pressure monitors are improved in various ways in terms of housing of the cuff as disclosed in Documents 2 and 3, almost no improvement has been made for the housing of the air tube. Thus, the user is entirely responsible for the act of housing the air tube. If the user handles the air tube carelessly, the air tube could be bent, twisted or caught between the main-unit casing and the open/close cover. In such a case, at the worst, the air tube could be broken.
In comparison with this, in the case where the structure disclosed in Document 1 is employed, since the composite tube including the air tube is thermally processed to have resilience in spiral manner, it is unlikely that the composite tube including the air tube is bent or twisted. However, if the composite tube is handled carelessly, the composite tube could be caught between the main-unit casing and the open/close cover, which could lead to breakage as well. Further, in the case where the structure as disclosed in Document 1 is employed, the resilience of the composite tube which is thermally processed into the spiral shape always exerts tension on the upper arm while the cuff is mounted on the upper arm. Thus, the accuracy in measurement could be adversely influenced or the user has to bear some inconvenience.